I'm not 100% certain of this, but I think they may be finishing reamers for taper pin holes.
The usual modern way of fitting taper pins is to drill in steps with parallel drills, then finish with a multi-flute taper reamer. Before such reamers were commonly (well, relatively commonly!) available, all sorts of dodges must have been used, some of which probably didn't leave a great finish. For a taper pin to work reliably, it does need to seat tight in a nicely finished hole, and I think the items in question were intended to be used almost as rotary scrapers to finish the pin seating. They aren't modern - probably a pre-WW1 solution. Why they have a round shank and not a square for a tap wrench I really don't know.
Standard taper pins are 1 in 48 taper, or 0.250" per foot of length, if that helps to check the taper of the tools.